One of our templates seems corrupted. We can't edit the page, even not show (yes, it exists) and so on. All this results in a time-out. Now we try to import a back-up version but also Special:Import gives a time-out.
How do I fix this?
Problem fixed (sort of), see https://sourceforge.net/p/semediawiki/mailman/message/36137641/ for details.